package com.cwz.gateway.filter;

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.OrderedGatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.http.HttpMethod;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.Collections;
import java.util.List;

/**
 * @program: w-demo
 * @description: 获取 body 请求数据（解决流不能重复读取问题）
 * @author: Wen
 **/
@Component
public class CacheRequestFilter extends AbstractGatewayFilterFactory<CacheRequestFilter.Config> {
	public CacheRequestFilter() {
		super(Config.class);
	}

	@Override
	public String name() {
		return "CacheRequestFilter";
	}

	@Override
	public GatewayFilter apply(Config config) {
		CacheRequestGatewayFilter cacheRequestGatewayFilter = new CacheRequestGatewayFilter();
		Integer order = config.getOrder();
		if (order == null) {
			return cacheRequestGatewayFilter;
		}
		return new OrderedGatewayFilter(cacheRequestGatewayFilter, order);

	}

	@Override
	public List<String> shortcutFieldOrder() {
		return Collections.singletonList("order");
	}

	public static class CacheRequestGatewayFilter implements GatewayFilter {
		@Override
		public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
			// GET DELETE 不过滤
			HttpMethod method = exchange.getRequest().getMethod();
			if (method == null || method == HttpMethod.GET || method == HttpMethod.DELETE) {
				return chain.filter(exchange);
			}
			return ServerWebExchangeUtils.cacheRequestBodyAndRequest(exchange, (serverHttpRequest) -> {
				if (serverHttpRequest == exchange.getRequest()) {
					return chain.filter(exchange);
				}
				return chain.filter(exchange.mutate().request(serverHttpRequest).build());
			});
		}
	}

	static class Config {
		private Integer order;

		public Integer getOrder() {
			return order;
		}

		public void setOrder(Integer order) {
			this.order = order;
		}
	}
}
